The goal of this project is to develop a method to image structures under living tissue with high resolution using optical techniques. Recent experimental results have demonstrated that one can image through turbid media using optical heterodyne techniques. These experiments were performed using available non-optimal equipment and no quantitative results were obtained. A chicken leg with a bone included was qualitatively imaged. A new theory is presented in this proposal, showing a heretofore not predicted further discrimination of heterodyne detection against the scattered light which would obscure the image. A properly designed optical heterodyne system is described. The system, limited by local oscillator noise and using a very narrow-band I.F. amplifier, will be built and quantitative data will be obtained of image detection through turbid media (e.g., skin). The minimum intensity of the cw incident light required in various medical applications will be determined. The replacement of x-ray with optical techniques for patients requiring repeated monitoring (such as possibly for tumors) will be particularly advantageous.